U.S. patent number 4,164,109 [Application Number 05/864,628] was granted by the patent office on 1979-08-14 for method and device for a tight packing under a thermoplastic and thermoformable film of products requiring an absolute protection.
Invention is credited to Jacques R. N. Dubois.
United States Patent |
4,164,109 |
Dubois |
August 14, 1979 |
**Please see images for:
( Certificate of Correction ) ** |
Method and device for a tight packing under a thermoplastic and
thermoformable film of products requiring an absolute
protection
Abstract
While thermoforming an article skin-wrap packaging, the article
being disposed on an air-tight supporting plate firmly applied on
an evacuated chamber and a plastic film displaced parallel to the
supporting plate to firmly engage the article and the supporting
plate, vacuum is provided in the wrapping by means of at least one
suction tube or nozzle temporarily placed between the supporting
plate and the film.
Inventors: |
Dubois; Jacques R. N. (75016
Paris, FR) |
Family
ID: |
9196856 |
Appl.
No.: |
05/864,628 |
Filed: |
December 27, 1977 |
Foreign Application Priority Data
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Oct 24, 1977 [FR] |
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77 31938 |
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Current U.S.
Class: |
53/427; 53/433;
53/509; 53/511 |
Current CPC
Class: |
B65B
11/52 (20130101); B65B 31/06 (20130101); B65B
31/043 (20130101) |
Current International
Class: |
B65B
31/04 (20060101); B65B 031/04 () |
Field of
Search: |
;53/22A,112A,427,509 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: McGehee; Travis S.
Attorney, Agent or Firm: Hauke and Patalidis
Claims
I claim:
1. A method for tight packaging an article under a thermoplastic
and thermoformable film comprising the steps of:
placing an air-tight support on an apertured plate of a chamber and
evacuating the chamber whereby the support is firmly applied onto
the plate,
positioning the article to be packaged on the support,
placing a thermoplastic and thermoformable film in an upright
sliding position in proximity to the top of the article,
providing at least one suction nozzle between the support and the
film,
connecting said suction nozzle to a vacuum source,
heating the film while simultaneously causing the film and the
nozzle to be displaced in unison parallel to the support towards
the article until the film engages the article and tightly wrap the
article and the suction nozzle on the support,
removing said suction nozzle from between the support and the
film,
and disconnecting said nozzle from the vacuum source.
2. The method of claim 1 wherein the film is made self-adhesive by
being provided with a coating of an adhesive material which can be
heated reactivated.
3. The method of claim 1 wherein the support is made self-adhesive
by being provided with a coating of an adhesive material which can
be heat reactivated.
4. An apparatus for forming a tight skinwrapped packaging of an
article under a thermoplastic and thermoformable film comprising
means for placing a thermoplastic and thermoformable film in a
sliding position in proximity to the top of said article positioned
on an air-tight support on an apertured plate of a chamber; means
for evacuating the chamber whereby the support is firmly applied
onto the plate; upright sliding means for slidingly moving the
film; at least one suction nozzle in a sliding position between the
support and the film; a vacuum source; means for connecting said
suction nozzle to the vacuum source; heating means for heating the
film; means for controlling heating of the film with a simultaneous
sliding of the film and the nozzle towards the article until the
film comes into wrapping engagement with the article and wrap the
film on the support, and means for removing said suction nozzle
from between the support and the film.
5. The apparatus of claim 4 wherein various pressing means are
further provided for ensuring a tight closing of the package upon
removal of said suction nozzle.
6. The apparatus of claim 4 wherein means are provided for
injection of a rare gas into the package thereby contributing to
the preservation of the packaged article.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a method and a device providing a
tight skinwrapped packaging under a thermoplastic and
thermoformable film of products requiring an absolute
protection.
There are already known packings formed by a thermoplastic film,
preferably of a tranparent material, placed on an article placed on
a porous or apertured support. This method is already used for
protecting and presenting under an attractive aspect articles
offered for sale. However, the porosity or the apertures of the
supporting material, required for the passage of the evacuated air
for applying the thermoplastic film, do not permit to obtain
hermetically sealed packages.
Consequently, the present invention has for its object to cope with
the disadvantage of the known packings, by providing a method and a
device which enable to obtain through applying a thermoplastic
film, display packages which are totally air-tight and ensure to
the articles therein an absolute protection against any outside
attacks such as microbial contamination, corrosion and the like.
The packages realized according to the method of the present
invention are particularly advantageous for food products, as well
as for previously sterilized articles and similar.
SUMMARY OF THE INVENTION
The method according to the invention is characterized in that
during the thermoforming of a skinwrapped package formed by
applying a stretchable plastic film on an article disposed on a
supporting plate with no porosities or perforations placed on the
plate of an evacuated chamber, a vacuum is created in the wrapping
itself by means of at least on suction tube temporarily engaged
between the supporting plate and the plastic film.
The device for carrying into effect the method of the invention is
characterized in that a conventional thermoforming machine
connected to a vacuum pump is provided with at least one vacuum pin
formed by a small tube which is automatically introduced between
the plastic film and the supporting plate, said vacuum pin being
automatically removed from between the plastic film and the
supporting plate at the end of the process.
Various other features of the invention are moreover shown in the
following description.
Embodiments of the present invention are shown, as non restrictive
examples, in the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a diagrammatic partial cross-sectional front view of a
machine for carrying into effect the method of the invention and
showing the first operative step.
FIG. 2 is a view similar to FIG. 1 but showing the final operative
step.
FIG. 3 is an enlarged cross-section showing the tooling necessary
for the realization of the method of the present invention.
FIGS. 4 and 5 are top views of the forming plate showing various
arrangements of vacuum pins and of pins for injection of rare
gases.
FIGS. 6 and 7 are cross-sectional views showing two different means
to crush the evacuation channel.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
For carrying into effect the method according to the invention,
there can be used a thermoforming machine of a conventional type
such as that represented diagrammatically in FIGS. 1 and 2. This
machine is mainly constituted by a frame 1, four columns 2, 3, 2a
and 3a (FIGS. 4 and 5) with only two columns 2 and 3 being shown in
FIGS. 1 and 2, an end plate 4, a mobile plate 5, and a device 6
which is adjustable in height.
The mobile plate 5, whose upwards or downwards movement is guided
by the columns 2, 2a, 3, 3a, is controlled by a jack or similar
means 7, comprises a caisson or chamber 8 connected through a
flexible duct 9 and a rigid duct 10 to a vacuum pump 11. In the
upper portion of the chamber 8, and slightly in recess relatively
to its upper edge, there is provided a perforated plate 12 on which
is placed the support 13 of the article 14 to be packaged.
The device 6 is provided, on one hand, to maintain the film
stretched and, on the other hand, to be used as a support for at
least one vacuum pin 16 which is formed by a cylinder or similar
means 17 and a small tube 18 connected by means of a flexible duct
19 to the rigid duct 10 coming from the vacuum pump 11. The duct 10
has two valves 20, 21 controlling the vacuum both at the level of
the chamber 8 and at the level of the pin 16. Due to the fact that
the device 6 is adjustable in height it can, depending on the
softening point of the thermoplastic film, be brought more or less
close to a heat source 22 formed, for instance, by an infrared
emitter.
The operation of the device of the invention is as follows: the
support 13 in the form of a supporting plate 1, made of cardboard
or other air-tight material, is placed on the perforated plate 12
of the chamber 8 where it is firmly held by the vacuum created in
the chamber 8 which communicates with the vacuum pump 11 because of
the opening of the valve 20. Then, the article 14 to be packed is
placed on the support 13 and, after having heat softened the film
15 by means of the heat source 22, the mobile plate 5 is taken
upwards, thus the film 15 takes the shape of the article 14 and is
marginally applied on the supporting plate 13, except where the
small evacuation tube 18 of the vacuum pin 16 is disposed. By
letting between the article 14 and the end of the tube 18 a
suitable distance d, the film 15 automatically engages the support
13 at the end of the vacuum step and upon removal of the tube 18.
For the purpose of increasing the air tightness of the package, it
is also possible to use simple mechanical means 23, i.e. either a
rod 24 subjected to the force of a spring 25 (FIG. 6), or another
pressing element 26 pressing the film 15 on the support 13 as soon
as the tube 18 of the pin 16 is removed. These pressing means 23
become particularly necessary when it is desired to inject into the
packing a rare gas before removing the vacuum pin. For that purpose
there is no objection to using various vacuum pins, as shown in
FIGS. 4 and 5.
In actual practice, it is possible to use thermoforming machines of
various types to obtain the same result. For example, a machine may
be used having a fixed plate but in which the film and its fixing
means move from top to bottom after having preheated the film in
such a way that it covers the article to be packaged.
The present invention is applicable to all packaging techniques
whatever may be the nature of the film or of the support utilized.
It is only important to obtain a perfect adhesion of the film on
the support. For that purpose, either the film or the support is
generally made self-adhesive by coating it with a varnish or with a
special glue which can be heat reactivated. There can also be used
two materials of same nature which can be thermosealed by a mere
pressure.
The invention is not restricted to the examples as above
represented and described for various modifications thereof may be
made without departing from the scope of the invention as defined
in the appended claims.
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